ASCRS Summer Refractive Congress highlights new technologies

Experts discuss approaches to managing complicated refractive surgery cases and protection from potential liability.

BOSTON — Using two types of multifocal IOLs in combination in bilateral refractive lens exchange reduces intermediate vision complaints. It also provides high rates of spectacle independence and patient satisfaction, according to a surgeon speaking here.

Frank A. Bucci Jr.

Frank A. Bucci Jr., MD, discussed strategies for using multifocal IOLs to treat presbyopic patients at the American Society of Cataract and Refractive Surgery Summer Refractive Congress. In particular, he addressed the benefits and limitations of presbyopia-correcting lenses, including the eyeonics crystalens, the Advanced Medical Optics ReZoom and the Alcon AcrySof ReSTOR.

In a study, Dr. Bucci and colleagues compared the postoperative visual results in 110 eyes of 55 patients implanted bilaterally with ReSTOR IOLs to 150 eyes of 75 patients implanted with a combination of one ReZoom IOL and one ReSTOR IOL.

The researchers found that patients implanted with the ReZoom/ReSTOR lens combination achieved better intermediate vision. Patients implanted with bilateral ReSTOR lenses achieved J1 bilateral near visual acuity (VA), J3.81 bilateral intermediate VA and J4.49 unilateral intermediate VA.

Patients who received a ReZoom lens in one eye and a ReSTOR lens in the other eye also achieved bilateral near VA of J1. However, these patients had significantly better results in the two other measurements, achieving J2.39 bilateral intermediate VA and J3.03 unilateral intermediate VA, Dr. Bucci said.

The ReZoom and ReSTOR lenses work together to counterbalance each other’s weaknesses, he said. The ReZoom lens provides strong intermediate vision, but patients can experience reduced near vision and light phenomena at night. The ReSTOR lens, on the other hand, provides less intermediate vision, but patients have stronger reading vision in bright light and fewer halos at night.

“The unique optical characteristics of each multifocal IOL appears to be complementary,” Dr. Bucci said.

What follows are additional highlights from the ASCRS Summer Refractive Congress. These items appeared first on the OSN SuperSite as daily news reports filed on-location at the meeting. Look to upcoming issues of OSN for expanded coverage of selected items.

Documentation, honesty protects against malpractice

Keeping detailed patient charts, documenting informed consent and accepting responsibility for errors when they occur can help refractive surgeons avoid costly malpractice suits, according to two attorneys.

“Patients lose trust with their doctor if their doctor minimizes or ignores their problems. Physicians should be aware of this, because if patients lose trust, they will look for other doctors or find their way to a plaintiff lawyer,” said Gregory K. Zeuthen, JD, a plaintiff’s attorney.

Mr. Zeuthen and Kevin E. Oliver, JD, a defense attorney, discussed the current medicolegal climate in refractive surgery in two keynote lectures. They outlined LASIK cases they have handled in court and possible approaches surgeons could employ to avoid litigation.

Mr. Oliver said he tells doctors to imagine a hypothetical situation in which all their charts have court exhibit stickers on them. He then asks them to carefully consider whether those charts are well documented and adequately clear to be used in a defense or a prosecution.

“You need to chart everything,” Mr. Oliver said.

Mr. Zeuthen noted that draconian documentation is the key to minimizing the risk of legal action. Should a case go to trial, it is also important for mounting a defense.

“Paranoia is not bad at all,” Mr. Zeuthen said. “It’s just a higher state of awareness. If you practice medicine with a higher state of awareness, you’re going to avoid more lawsuits.”

Both lawyers noted that surgeons should be honest when dealing with refractive surgery mistakes or errors. Most refractive surgery patients are highly educated individuals who understand the legal system and will sue if not treated appropriately, they said.

“It’s how a bad outcome is dealt with in your office that determines whether a patient will go to another doctor or to a plaintiff’s lawyer,” Mr. Zeuthen said.

Wavefront enhancements aid complication management

Roger F. Steinert, MD, discussed issues and limitations associated with wavefront technology. He noted that wavefront-guided enhancement can be an effective treatment for many corneas with irregular shapes resulting from previous refractive surgery. The custom treatments can be especially effective when used with small laser spot size, accurate registration, a good eye tracker and a wide treatment zone.

He noted that while wavefront technology is widely used for enhancement procedures, researchers have had inconsistent results using the technology on optically challenged corneas.

“Wavefront algorithms are optimized for primary treatments, where the low-order aberrations, sphere and cylinder are much larger than the higher-order aberrations,” he said.

Dr. Steinert presented several cases in which patients with previous refractive surgery were treated with wavefront-guided corrections. In one case, a 40-year-old woman underwent LASIK that was complicated by a microkeratome pass that stopped short nasally. The surgeon applied laser ablation without shielding the underside of the flap. When the flap was replaced, the patient had high coma, an untreated mid-periphery and a doubly ablated central optical zone, Dr. Steinert said.

In the enhancement, a wavefront-guided PRK was performed on the flap, ablating to a central depth of 19.1 µm, he said.

Prevention key to avoiding LASIK complications

Comprehensive preoperative evaluation and screening of LASIK patients is imperative to preventing both intraoperative and postoperative complications, noted Helen K. Wu, MD.

Helen K. Wu

She noted that severe LASIK complications are rare, but common complications, such as dry eye, can reduce postop uncorrected visual acuity. However, many complications are avoidable with careful planning, appropriate patient counseling and a meticulous intraoperative technique.

For dry eye and blepharitis, the best management approaches include nonpreserved artificial tears, emulsions, gels and ointments. Silicone plugs can also be effective in many patients, she noted.

“When we do see complications, addressing them and treating them early will help prevent significant loss of vision and further headaches,” she said.

Soldiers prefer surface ablation over LASIK

U.S. Army soldiers at Fort Bragg most commonly receive PRK and LASEK, citing the procedures’ visual outcomes and longer leave time to receive surgery, according to a military surgeon.

Scott D. Barnes

Scott D. Barnes, Lt. Col., MC, USA, discussed front-line soldiers’ needs for refractive surgery and the types of procedures most commonly performed. He focused on refractive laser procedures performed at the Fort Bragg U.S. Army base in North Carolina — the Army’s first laser surgery center and now one of eight Warfighter Refractive Eye Surgery Programs.

All soldiers at the base can receive surgery free of charge and are allowed to choose whichever procedure best suits them, he said. Most of Fort Bragg’s soldiers — 60% — prefer receiving PRK, 24% prefer LASEK, and 16% prefer LASIK, according to Dr. Barnes. Many soldiers choose PRK because of its longer recovery period — 4 days compared to LASIK’s two-day recovery, he said.

Refractive surgery is popular at the base not only because it can improve soldiers’ daily lives, but because it can also be advantageous in both day and night combat situations, where eyeglasses can prove to be life threatening, Dr. Barnes noted.

“When a solider has been captured, and he’s lost his glasses and can’t see to escape without them, that’s a major issue,” Dr. Barnes said. “We have, essentially, an unlimited waiting list. We’ve got eight years’ worth of wait for one base alone.”

Thin flap LASIK has advantages

LASIK with a 100-µm flap induces less corneal weakness than LASIK with thicker flaps, allowing higher power corrections, according to Michael C. Knorz, MD.

Early LASIK procedures often involved thin corneal flaps, but complications led to the use of thicker flaps, in the range of 130 µm to 180 µm. However, the introduction of femtosecond lasers, such as the IntraLase FS laser, is bringing renewed interest to performing LASIK using thinner flaps, he said.

“It’s a pretty much straightforward procedure,” he said. “We weaken the cornea less, which is definitely an advantage.”

Dr. Knorz cited a retrospective study of 280 eyes by Rosario Cobo-Soriano and colleagues, published in the Journal of Cataract and Refractive Surgery. Those authors found that patients with thin flaps achieved better uncorrected visual acuity compared with patients with thicker flaps. They also had lower re-treatment rates and better contrast sensitivity.

However, thinner flaps have some drawbacks, Dr. Knorz said. Flaps around 100 µm thick have less of an adverse biomechanical effect, but they are not as stable as thicker flaps. Thinner flaps can also increase the risk of flap-related complications, and excessively thin flaps, ranging from 70 µm to 80 µm, do not appear to be as effective, Dr. Knorz said.

“We should probably stay around 100 µm,” he said.

Numerous risk factors for corneal ectasia

Chronic trauma induced by eye rubbing may be an important potential risk factor for corneal ectasia, said R. Doyle Stulting, MD, PhD, a keynote speaker at the meeting.

According to Dr. Stulting, both a family history and premature birth could increase patients’ risks. Other probable risk factors include eye rubbing, increased astigmatism and biomechanical instability, while possible risk factors include keratocyte abnormality and the use of mitomycin-C.

“Don’t ignore red flags, especially when there are more than one,” he said. “Some patients will develop ectasia even with normal topographies, even after PRK.”

Dr. Stulting and colleagues at Emory University recently studied 27 eyes of 25 patients with a mean age of 27.8 years. The researchers had carefully selected patients who had the fewest ectasia risk factors possible. All patients underwent PRK, with a mean predicted ablation depth of 85.3 µm, according to Dr. Stulting.

The researchers found it took an average of 14.8 months following surgery to recognize the onset of ectasia. Also, the estimated incidence was about 1 in 2,500 cases, but that data could be an under- or overestimate, Dr. Stulting said.

Toric lens an option in keratoconus

The toric version of STAAR Surgical Co.’s Visian ICL, currently in U.S. clinical trials, is showing potential for treating patients with myopic astigmatism, with early clinical results showing patients achieving good vision at 1 year.

The Visian Toric ICL (TICL) may also have applications for some patients with keratoconus, according to John A. Vukich, MD.

“The intraocular option is growing as a reasonable choice we can offer our patients,” he said.

In a study of 19 eyes of 15 patients with keratoconus, researchers found that best-corrected visual acuity improved following implantation of the lens.

Preoperatively, spherical equivalent was –2 D to –6 D in 36.8% of eyes, –6.1 D to –10 D in 42.1% of eyes, –10.1 D to –14 D in 10.5%, and –14.1 D to –19 D in 10.5%. Postoperatively, 44% of patients gained one line of Snellen visual acuity, 19% gained two lines, and 31% had no loss or gain of BCVA.

Implants show promise for emmetropic presbyopes

Small-diameter intracorneal inlays are a promising technology for treating presbyopia in emmetropic patients, according to Dr. Steinert, MD.

Roger F. Steinert

Dr. Steinert discussed the potential for the implants on behalf of Richard L. Lindstrom, MD, who was unable to present. He outlined the results of preliminary trials of four intracorneal lenses: Bausch & Lomb’s Chiron lens, Biovision’s Invue Intracorneal Microlens system, the Intralens Multifocal Cornea and the AcuFocus small diameter intracorneal inlay.

Bausch & Lomb’s Chiron implant was well tolerated biologically in a preliminary study, with few pigment deposits seen on the device. Of eight patients implanted monocularly with the lens in a modified monovision approach, 75% never wear glasses, Dr. Steinert said.

Biovision’s Invue Intracorneal Microlens system had a high level of patient satisfaction in a preliminary clinical study, he said, with patients immediately regaining near vision after surgery.

The Intralens Multifocal Cornea, which is further along in development, is demonstrating good results in U.S. clinical trials for hyperopia, Dr. Steinert said. The implant is showing “promising” results for treating presbyopia, he said.

In clinical studies of the AcuFocus Corneal Inlay, patients are also achieving significant improvements in near visual acuity, with no loss of distance vision, he said.

Placido-based corneal topography outdated

Current placido-based corneal topography systems assume all corneas conform to a known conic section, not allowing for a more true shape representation, noted Michael W. Belin, MD, also a keynote speaker at the meeting.

According to Dr. Belin, topographic analyses based only on placido-derived anterior curvature are incomplete; they show the corneal apex, line of sight and video keratoscopy axis as the same.

He noted that in a study involving Bausch & Lomb’s Orbscan, the device incorrectly read the corneal thickness of one patient as being 37 µm thinner. It also showed an incorrect ectasia.

“It is like relying on an X-ray when an MRI is available,” Dr. Belin said.

In comparison, elevation data is independent of axis, orientation or positioning, according to Dr. Belin. He said all further maps of curvature can be derived from accurate elevation data.

“Keratoconus screening requires the use of topography systems that measure elevation data as their elemental requirement,” he said

Wavefront technology shows eye’s changes with age

Wavefront technology can assist in charting the aging process in a patient’s eye, according to Kevin L. Waltz, OD, MD.

“We’re just beginning to understand how the eye ages with wavefront technology. It ages very differently from what you and I would expect,” he said.

As an example, Dr. Waltz described wavefront measurement changes in his son at different time points. At 13 years of age, the eyes show little to no change in aberrations during accommodation. Measurements at ages 19 and 23 years showed similar results — little change in aberrations with accommodation — but changes began to increase.

By a person’s late 20s and early 30s, alterations in accommodation are beginning “very gradually, very steadily,” Dr. Waltz said.

In wavefront maps of patients in their 40s, the wavefront summary displays showed that mild cataracts are forming, Dr. Waltz said. Cataracts cause opacity that attenuates the light entering the eye, and they also cause higher-order aberrations, scattering photons as they pass through the lens, he said.

Fusarium keratitis outbreaks show vigilance is needed

Terrence P. O'Brien

Awareness of the possibility for further outbreaks of Fusarium keratitis among soft contact lens wearers could lead to earlier diagnosis and treatment, said Terrence P. O’Brien, MD.

He noted the recall in May of Bausch & Lomb’s ReNu with MoistureLoc solution and its possible link to recent Fusarium keratitis outbreaks reported in Singapore, Hong Kong and the United States.

The explanation for the outbreaks that was proposed by Bausch & Lomb was multifactorial, including poor patient compliance with lens care regimens, susceptibility of the wearer to infection, and a protection of Fusarium deposits by the surfactants in the MoistureLoc solution, he said. Use of certain types of soft contact lens may also have affected the normal inflammatory response of the eye, he added.

“Ophthalmic clinicians should have a heightened clinical suspicion for possible Fusarium and other fungal pathogens as causative agents in cosmetic soft contact lens patients presenting with ulcerative keratitis,” he said.

For more information:

• ASCRS Summer Refractive Congress 2007 will be held August 2-5, 2007, at the Four Seasons Aviara, North San Diego, Calif.

• Erin L. Boyle is an OSN Staff Writer who covers all aspects of ophthalmology.